1. Technical Field
The present disclosure relates to a liquid crystal display.
2. Discussion of Related Art
A liquid crystal display (LCD) is one of the most widely used flat panel displays. An LCD may include two panels provided with pixel electrodes and a common electrode (commonly referred to as “field generating electrodes”) and having a liquid crystal (LC) layer interposed between the two panels. An LCD generates an electric field in the LC layer by applying voltages to the field generating electrodes. When an electric field is applied, the LC molecules in the LC layer are tilted with respect to an axis normal to the panels at angles dependent on the strength of the electric field. The LCD displays images by controlling the strength of the electric field, which determines orientations of LC molecules to adjust polarization of incident light.
An LCD further includes switching elements connected to the pixel electrodes and a plurality of signal lines such as gate lines and data lines for controlling the switching elements to apply voltages to the pixel electrodes.
A vertical alignment (VA) mode LCD, in which longitudinal axes of the LC molecules are aligned perpendicular to the two panels in the absence of an electric field, can produce a relatively high contrast ratio and wide reference viewing angle.
The wide viewing angle of the VA mode LCD can be realized by cutouts or protrusions on the field-generating electrodes. Since the tilt directions of the LC molecules are determined by the cutouts or the protrusions, the tilt directions can be distributed into several directions by appropriately arranging the cutouts and the protrusions such that the reference viewing angle is widened.
However, the protrusions and the cutouts may obstruct the passage of incident light, and the light transmittance may decrease as the number of protrusions or cutouts increases. In one method to increase the light transmittance, the area of the pixel electrodes is enlarged. However, in such a configuration, strong lateral electric fields are generated near the edges of the pixel electrodes. The lateral electric fields disorder the orientations of the LC molecules which generates texture and light leakage and lengthens the response time.
In addition, the VA mode LCD may have poor lateral visibility as compared with frontal visibility. For example, in a conventional LCD provided with cutouts in the field-generating electrodes, the luminance is enhanced toward the display's lateral sides, and, in a the worse case, the luminance difference between high grays vanishes such that the image cannot be perceived.